In part 2 we showed that the position of the implicit bit i was also the width of the biased exponent. That makes the bias i-1 bits wide. Since all bits of the bias are 1, the value of the bias is 2^i-1-1. With one bit for the sign, that leaves n-i-1 bits for the width of the significand. By specifying i as a function of n the storage format becomes fully defined. This works not only for eight-bit boundaries but for the six-bit boundaries of Color My Data eight-bit compressed binary format (CBF8). CBF8 is designed for loss-less data exchange using binary formats. One base-64 digit could represent plus or minus sixteenths between 0 and 0.9375; eighths between 1 and 1.875; fourths between 2 and 3.75, infinity, quiet NaN or NaN with up to two signals. That represents a potential compression of 87.5% over double precision WITH NO LOSS OF DATA.
The graph below shows how i varies with n in comparison to the current standard.

The graph was generated from the following tables. Here are the column definitions.
Bytes (Digits):

Data storage size in bytes or base-64 digits

Bits:

Data storage size in bits (8 bits per byte; 6 bits per base-64 digit)

Sign:

The sign is a one-bit value

BiasExp:

The width, i of the biased exponent in bits

Significand:

The width of the significand in bits

Precision:

The number of decimal digits of precision (Ada digits)

DynRange:

Twice the bias converted to decimal digits

bytes	bits	sign	biasExp	significand	precision	bias	dynRange
1	8	1	3	4	1.20	3	1.81
2	16	1	5	10	3.01	15	9.03
3	24	1	7	16	4.82	63	37.93
4	32	1	8	23	6.92	127	76.46
5	40	1	9	30	9.03	255	153.53
6	48	1	10	37	11.14	511	307.65
7	56	1	10	45	13.55	511	307.65
8	64	1	11	52	15.65	1023	615.91
9	72	1	11	60	18.06	1023	615.91
10	80	1	12	67	20.17	2047	1232.42
11	88	1	12	75	22.58	2047	1232.42
12	96	1	13	82	24.68	4095	2465.44
13	104	1	13	90	27.09	4095	2465.44
14	112	1	14	97	29.20	8191	4931.47
15	120	1	14	105	31.61	8191	4931.47
16	128	1	15	112	33.72	16383	9863.55

digits	bits	sign	biasExp	significand	precision	bias	dynRange
1	6	1	2	3	0.90	1	0.60
2	12	1	4	7	2.11	7	4.21
3	18	1	5	12	3.61	15	9.03
4	24	1	7	16	4.82	63	37.93
5	30	1	8	21	6.32	127	76.46
6	36	1	8	27	8.13	127	76.46
7	42	1	9	32	9.63	255	153.53
8	48	1	10	37	11.14	511	07.65
9	54	1	10	43	12.94	511	307.65
10	60	1	11	48	14.45	1023	615.91
11	66	1	11	54	16.26	1023	615.91
12	72	1	11	60	18.06	1023	615.91
13	78	1	12	65	19.57	2047	1232.42
14	84	1	12	71	21.37	2047	1232.42
15	90	1	13	76	22.88	4095	2465.44
16	96	1	13	82	24.68	4095	2465.44
17	102	1	13	88	26.49	4095	2465.44
18	108	1	14	93	28.00	8191	4931.47
19	114	1	14	99	29.80	8191	4931.47
20	120	1	14	105	31.61	8191	4931.47
21	126	1	15	110	33.11	16383	9863.55
22	132	1	15	116	34.92	16383	9863.55