Out for a Lark

Here's a class idea I wanted to play around with ever since I read the description in Ultima III.

LARK
The predecessors of bards and jesters, larks studied Sorcery and were known to pick the odd pocket or loot an unguarded chest. They were trained in the use of all weapons, but only wore cloth armor.

Requirements: None
Prime Requisite: STR + INT
Hit Dice: 1d6
Maximum Level: None

Because of their need of free movement, larks cannot wear armor heavier than padded, and they cannot use shields. They have a need for using diverse weapons, and are able to use any kind.

Lark Level Progression
Experience	Level	Title	Hit Dice (1d6)
0	1	Bumbler	1
2,501	2	Dawdler	2
5,001	3	Caperer	3
10,001	4	Tomfool	4
20,001	5	Fol	5
40,001	6	Disour	6
80,001	7	Bourder	7
160,001	8	Lark	8
310,001	9	Master Lark	9
460,001	10	Master Lark	+1 hp only*
610,001	11	Master Lark	+2 hp only*
760,001	12	Master Lark	+3 hp only*
910,001	13	Master Lark	+4 hp only*
1,060,001	14	Master Lark	+5 hp only*
1,210,001	15	Master Lark	+6 hp only*
1,360,001	16	Master Lark	+7 hp only*
1,510,001	17	Master Lark	+8 hp only*
1,660,001	18	Master Lark	+9 hp only*
1,810,001	19	Master Lark	+10 hp only*
1,960,001	20	Master Lark	+11 hp only*

* Hit point modifiers from constitution are ignored

Spell Progression and Skills
Class Level	Cantrip*	1	2	3	4	Pick Locks	Find/Remove Traps	Pick Pockets**
1	1	-	-	-	-	17	14	23
2	1	1	-	-	-	20	17	26
3	2	1	-	-	-	23	20	29
4	2	2	1	-	-	26	23	32
5	2	2	1	-	-	29	26	35
6	3	2	1	1	-	32	29	38
7	3	2	2	1	-	35	32	41
8	3	3	2	1	1	38	35	44
9	4	3	2	1	1	41	38	47
10	4	3	2	2	1	44	41	50
11	4	3	3	2	1	47	44	53
12	5	4	3	2	2	50	47	56
13	5	4	3	2	2	53	50	59
14	5	4	3	3	2	56	53	62
15	6	4	4	3	2	59	56	65
16	6	5	4	3	3	62	59	68
17	6	5	4	3	3	65	62	71
18	7	5	4	4	3	68	65	74
19	7	5	5	4	3	71	68	77
20	7	6	5	4	4	74	71	80

*Cantrips are optional, see Unearthed Arcana.
** -5% per each 5 levels the lark is lower than the victim. There is always a 1% chance of failure despite a skill percent above 100%.

Lark Saving Throws
Level	Breath Attacks	Poison or Death	Petrify or Paralyze	Wands	Spells or Spell-like Devices
1-4	16	14	13	13	14
5-8	14	12	11	11	12
9-12	12	10	9	9	8
13-16	10	8	7	5	6
17+	8	6	5	4	4