Recipe adjustments for a partial mash

[BrewMonkey]

I have a question relating to recipe adjustment - whether it is possible to closely match an AG recipe by substituting pale malt with light LME (john bull or similar). For example, the recipe below:

TEA Hogs Back
25 litre batch OG 1044 ABV 4.2%
PIPKIN PALE MALT 4303 gms
CRYSTAL MALT 349 gms
HOPS boil time 90 minutes
FUGGLES 35 gms
GOLDINGS 33 gms
Add 10 gms Goldings last 15 minutes.
Yeast of your choice

Is it possible to do a partial mash (in my soon-to-be-built boiler, watch this space for details) using crushed crystal malt in a hop bag, and substitute the pipkin for light LME? If so, how will I adjust for the quantity? The reason that I ask is just that I`d like to follow a few recipes but I`m not quite `on-it` with AG (yet)

[BrewMonkey]

Aaah, excellent. Thanx