Most varnish products will probably not play nice with most glues.
The glue will "bond" to the finish rather than the wood. With no
pores there is no penetration so any bonding will be electrostatic
rather than mechanical.
Traditional varnish is boiled linseed oil "cooked" with shellac - organic solvents.
These days polyurethane seems to be more popular and there are
water based varieties. It is a synthetic plastic.
If you are doing an upscale modern yacht, varnished decks may be appropriate.
You wear no scuff deck shoes to walk on them.
For most other classes of wooden ships, a slick varnished deck would be really
dangerous for the crew.
Because of scale effect, a flat or egg shell finish even for high gloss prototypes -
or at most matte..
You might consider super blonde shellac at half strength ( 5%) * and rub it down
with 0000 steel wool or a Scotch Brite pad. In any case, if you intend to apply a
finish before adding and gluing down additional components - it would be wise to
occlude the glue sites with painters tape or masking tape.
* orange shellac is full strength at 20 lb cut ( ~ 20% solution in methanol,
ethanol (denatured) or ( Pharmco grain - 95% - if you do not mind paying the taxes),
or anhydrous isopropyl.
It will darken the wood.
super blonde shellac is a very light amber. The purification process removes components
that help solubilize it - so - full strength is 10 lb cut ( ~10%). Primer or 1st coat = 5%.
There is a bit clearer grade: plantina shellac flakes - but it is not that lighter and costs about
twice what super blonde costs.