Both are phenomenal actions.
The 40X would be the better choice for a Palma rifle as the action is a bit lighter and you have a bit more leeway with weight on the F-Class rifle.
The weight restrictions are on F Class not TR under the new ICFRA rules.
ICFRA Rules for TR
"T2.2. Weight: There is no weight limit placed on the rifle."
ICFRA Rules for F Class
F2.2. An ‘F’ Class Open rifle may be of any calibre up to and including 8mm and the overall
weight must not exceed 10kg including all attachments (such as, but not limited to, its sights
and bipod, if any). NB: An ‘attachment’ is defined as including any external object (other
than the competitor, his sling (if any) and his apparel) which recoils (or partially recoils)
with the rifle, or which is clamped, magnetically or viscously held, or in any other way
joined to the rifle for each shot, or which even slightly rises with the rifle when vertically
lifting the latter from its rest(s).
F2.3. An ‘F’ Class Restricted rifle is limited to .223 Remington or .308 Winchester calibre
chambers or their commercial metrification equivalents. Chamber dimensions must conform
to SAAMI or CIP dimensions. Ammunition may be commercially made or hand-loaded as
defined in Rule F2.23. There is no restriction on bullet weight. The Restricted rifle class is
limited to the use of an attached bipod and/or a sling as front supports, optionally together
with a rear bag which provides no positive mechanical means of returning the rifle to its
precise point of aim for the next shot . The overall weight must not exceed 8.25kg including
all attachments (such as, but not limited to, its sights and bipod, if any). NB: An ‘attachment’
is defined as in Rule F2.2. All other Technical Rules apply.